In a communications system, a backplane is an important composition part of a communications device, generally includes multiple layers of printed circuit boards (PCB) boards and connectors, and provides functions of electrical signal connection and physical support for each subcard and module in the communications system.
With continuous development of a communications system technology, a large capacity requirement of the communications system requires a higher signal transmission rate in the backplane and a greater channel for signal transmission, and further, requirements for a quantity of layers, size, and density of conductive patterns in the PCB board of the backplane are higher. Moreover, the high transmission rate has higher requirements for an insulation material of the PCB board and precision of the conductive pattern in the PCB board. However, in a conventional PCB manufacturing technology, addition of the quantity of layers of the conductive patterns in the PCB board directly leads to an exponential growth of manufacturing difficulty and manufacturing costs of the PCB board, and even leads to a case in which processing cannot be performed. In addition, because the conductive pattern in the PCB board is processed by means of etching, the size and the precision of the conductive pattern cannot satisfy a requirement of high-rate signal transmission in an internal system.
Therefore, the prior art provides a backplane. Referring to FIG. 1 and FIG. 2, in the backplane, a PCB board is divided into a large backplane 01 and a group of small backplanes 02, and the large backplane 01 and the small backplanes 02 are assembled in a laminated manner. The large backplane 01 is used for transmission of a power source, transmission of a power source and a low-rate signal, and the small backplanes 02 are used for transmission of a high-rate signal, transmission of a high-rate signal and a low-rate signal, light transmission. The small backplanes 02 may be independent of the large backplane 01 and are assembled and disassembled in a manner of a chassis. Further, referring to FIG. 2, signal connection is implemented between subcards 03 and the large backplane 01 by means of insertion of connectors 04, and signal connection is implemented between the small backplanes 02 and the large backplane 01 by means of insertion of connectors 05.
Although the backplane with the foregoing structure separates wiring of the high-rate signal and configures the wiring in the backplanes 02, the signal transmission rate in the small backplanes 02 is still limited by a conventional PCB board manufacturing process, further leading to poor transmission quality and a low transmission rate of the high-rate signal in the communications device and an inflexible arrangement manner of a signal channel in the communications device.